Wireline operations are used in the tubing of oil and/or gas wells to perform various operations such as running and removing various well tools. However, high pressure in the well requires that a proper seal must be maintained around the wireline because the escape of well fluids and gases may present a major hazard. However, sealing against the wire, particularly when high well pressure is encountered, increases the friction against the wireline and consequently increases the amount of weight required to pull the wireline downhole against well pressure as well as the force to pull the wireline upwardly through the seal. These requirements have shortened the depths at which the wireline operation may be performed. While grease injector heads have been used in the past in stranded line operations, they have not been used on smooth wire. In addition, gas rises and expands and reduces the sealing effect of grease.
The present invention is directed to a grease injection control head, which is particularly useful for use with a smooth wireline, for conducting wireline operations in a well which provides an effective seal, with reduced friction on the wireline, and which reduces the adverse effect on the seal of gas in the well.